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E. M. Demin, E. V. Proskurnina, Yu. A. Vladimirov
Antioxidant
effects of dihydroquercetin and rutin in peroxidase reactions catalyzed by
cytochrome c
Abstract
Lipid peroxidation catalyzed by the complex of cytochrome c
and cardiolipin is a key event of apoptosis. Native peroxidase activity of
cytochrome c is weak, but it
increases manifold when cytochrome c bounds with
cardiolipin. In this work, we studied the effect of cardiolipin from bovine
heart (BCL) and synthetic 1,1’,2,2’-tetraoleyl cardiolipin (TOCL) on cytochrome
c peroxidase activity detected by luminol-enhanced chemiluminescence. It
is shown that chemiluminescence amplitude increases significantly in the range
of molar ratios of cardiolipin and cytochrome c approximately of 0 to 30
and 0 to 50 for TOCL and BCL, respectively. It increases insignificantly upon a
further increase in these ratios to 640 : 1 and 320 : 1
mol : mol. Such a character of the dependence of the
chemiluminescence amplitude on the ratio of cardiolipin and protein may be
accounted for by attaining the saturation of the protein surface with
cardiolipin molecules. For a ratio of BCL to cytochrome c of 32 : 1
mol : mol, the effect of antioxidants, rutin and dihydroquercetin, on
peroxidase activity of cytochrome c in the presence of coumarine C-525
as a chemiluminescence activator was studied. For both antioxidants, a decrease
in peroxidase activity was observed on an increase in antioxidant concentration
in the system. A 50% inhibition of the reactions was observed for antioxidant
concentrations of 10 µM for dihydroquercetin and 3 µM for rutin. It is supposed
that the use of antioxidants would provide the control of the key stage of
apoptosis, the formation of lipid radicals at membrane-bonded cytochrome c.
Copyright (C) Chemistry Dept., Moscow State University, 2002
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